07-08-2012, 03:01 PM
ARTIFICIAL SATELLITE
SATELLITES SEMINAR.pptx (Size: 681.88 KB / Downloads: 41)
Introducation
An artificial satellite is a manufactured object that continuously orbits Earth or some other body in space.
Artificial satellites also have orbited the moon, the sun, asteroids, and the planets Venus, Mars, and Jupiter. Such satellites mainly gather information about the bodies they orbit.
Artificial satellites differ from natural satellites, natural objects that orbit a planet. Earth's moon is a natural satellite.
Satellite orbit
In terms of altitude satellite are
classified as:
Low earth orbit satellite
Middle earth orbit satellite
Geostationary earth orbit satellite
Uses of Geostationary Orbits
Geostationary orbits are primarily used for two functions:
Weather monitoring
Telecommunications & Broadcasting
Commercial growth is focused on:
DTH TV (Direct To Home: Sky TV)
Phone, Fax, Video, Data services
Mobile Communications
Digital Radio
How do communication satellites work?
Two stations on earth want to communication through Radio broadcast but are too far away to use conventional means.
The two stations can use a satellite as a relay station for their communication one earth station sends transmission to the satellite. This is called a uplink.
The satellite transponder converts the signal and sends to the second earth station. This is called a downlink.
Satellite Uplink and Downlink
Downlink
The link from a satellite down to one or more ground stations or receivers
Uplink
The link from a ground station up to a satellite.
Some companies sell uplink and downlink services to
television stations, corporations, and to other telecommunication carriers.
A company can specialize in providing uplinks, downlinks, or both.